Investigations into the Holocene geology of the Dead Sea basin

Abstract

This paper discusses the geological history and paleoclimate of the Dead Sea region based on drill hole data. A composite stratigraphic column for the Holocene period, of multiple lime carbonate and halite sedimentation, has been constructed for the southern Dead Sea basin. Integration of stratigraphic data with geochronology has shed new light on our understanding of Holocene sedimentation rates, tectonics, diapirism, the formation of sinkholes, lake levels, and paleoclimate. During this period, the southern basin has subsided at a rate of 8.5–11 m/ka, while the subsidence of the northern basin may have reached 25–30 m/ka. The Holocene has been divided into 13 major climatic intervals, starting with a very arid climate from ~ 11,700 to ~ 8800 BP, where halite precipitated in both basins, with the Dead Sea possibly reaching a level of ~ − 419 m msl. After ~ 8800 BP, there was a very intense pluviatile period, with the formation of alluvial fans opposite wadi channels reaching up to 45 m in thickness. An attempt has been made to construct a new Dead Sea-level curve, based on the mineralogical data and corrected for diapirism under the Lynch Straits and tectonic subsidence. The previous lake-level curves were based on elevations of shore-line facies in a tectonically active basin with differential subsidence. A new hypothesis is presented for sinkhole formation in both the northern and southern basins, which is considered to be initiated and controlled by active faulting, with the dissolution of the halite by artesian, undersaturated waters, more than the receding Dead Sea level. The brine level is rising in the southern basin. The findings from this research can act as a model for understanding the development of ancient and modern evaporites worldwide.

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Acknowledgements

Special thanks are due to Chief Civil Engineer, Semion Kogan, of the Dead Sea Works Ltd., for his continual support and understanding that geology is the basis for sound engineering practices for construction, in such a demanding location. I would like to thank Prof. Sam Frydman for critically reviewing this paper and for providing constructive comments that greatly improved this paper.

14C age is reported in conventional radiocarbon years (before present = 1950) in accordance with international convention (Stuiver and Polach 1977). Thus all calculated 14C ages have been corrected for the fractionation so as to refer the results to be equivalent with the standard δ13C value of − 25‰ (wood). Calibrated ages in calendar years have been obtained from the calibration tables in Reimer et al. 2004, Radiocarbon vol. 46 by means of the 2005 version OxCal v. 3.10 of Bronk Ramsey

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